Enter the DarkSide Stefano Davini University of Houston RICAP-13

The DarkSide LNGS Direct WIMP search in low background Argon detector NULL background strategy unambiguos discovery with few WIMP-candidate events

The DarkSide Project DS-10 kg Tech. prototype – no DM goal Operated, Success DS-50 kg GOAL:   cm 2 Under Commissioning DS-50 ton GOAL:   cm 2 Future (G2)

The DarkSide detector TARGET underground Argon depleted in 39 Ar DETECTOR two-phase Argon Time Projection Chamber VETO & SHIELD Borated Liquid Scintillator VETO combined with Water Cherenkov detector to kill neutron background

Two Phase Argon TPC

Towards Null Background (1) Shape of the scintillation signal (PSD) Ratio between ionization and scintillation (S2/S1) 3D localization of the event (fiducialization) Rejection of electron/gamma background

Towards Null Background (2) Underground Argon depleted in 39 Ar 150 times more radiopure than atm Ar ( < 6.5 mBq/kg)

Towards Null Background (3) DarkSide detector

Towards Null Background (4) Active Neutron Veto, gets rid of neutron background 10 B(n,  ) 7 Li

Towards Null Background (5) Detection of muons, shield external neutron, Get rid of muon-induced backgrounds.

DarkSide-50 Expected Background “Null” Background Unambiguos discovery with few WIMP-candidate events

DarkSide-50 Sensitivity

Recent Milestones DS-10 Prototype operated for 1 year DS-50 All facilities are built 2 Rn-free clean rooms, Ar recirculation, purification, recovery systems Time Projection Chamber Assembled and deployed in the Neutron Veto Sphere. Filling with natural Argon completed. Now Under Commissioning Neutron Veto Construction and assembly of the Sphere completed, Reflectors (Tyvek) installed, 110/110 PMTs installed, Cameras installed Water Tank (CTF) Existing facility (Borexino-CTF) Installation of Reflectors (Tyvek) almost completed

DarkSide-10 Activities and Results Prototype, not physics capable Record Light Yield: 8.9 pe/keVee Pulse Shape Discrimination: Development of model for PSD HHV System: Long-term test succesful

DarkSide-50

Reflectors and PMTs installed inside the Neutron Veto Sphere

DarkSide-50 View of Neutron Veto Sphere from the Water Tank After installation of reflector (Tyvek)

DarkSide-50 TPC Assembled, Deployed

Conclusions and outlook We are entering the dark age. Depleted Argon is a reality. Argon 2-phase technology combined with Borexino liquid scintillator technology looks very promising for dark matter detection.

Augustana College, USA APC Paris, France Black Hills State University, USA Fermilab, USA IHEP, China INFN Laboratori Nazionali del Gran Sasso, Italy INFN and Università degli Studi Genova, Italy INFN and Università degli Studi Milano, Italy INFN and Università degli Studi Napoli, Italy INFN and Università degli Studi Perugia, Italy INFN and Università degli Studi Roma 3, Italy IPHC Strasbourg, France Jagiellonian University, Poland Joint Institute for Nuclear Research, Russia Princeton University, USA RRC Kurchatov Institute, Russia SLAC, USA St. Petersburg Nuclear Physics Institute, Russia Moscow University, Russia Institute for Theoretical and Experimental Physics, Russia Institute of Nuclear Research, Ukraine Temple University, USA University College London, UK University of Arkansas, USA University of California at Los Angeles, USA University of Chicago, USA University of Hawaii, USA University of Houston, USA University of Massachusetts at Amherst, USA Virginia Tech, USA University of Virginia, USA The DarkSide Collaboration